Hello there

For your kind information I want to tell you that there are two different Agencies which manages  examinations to fill the vacancies in CBI and these two Agencies are namely UPSC and SSC.

Now if you want to become a group A officer in CBI then you need to become an IAS officer which you can by passing the civil services examinations which is conducted by Union Public Service Commission (UPSC).

And if you want to become a sub inspector in CBI then  you have to qualify SSC CGL examination and SSC CGL conduct 2 tire examinations of the objective type for this post.

Eligibility for any candidate is that he or she must have a bachelor's degree from any recognised University.

To know more about SSC CGL examination you can refer the link:

https://competition.careers360.com/exams/ssc-cgl

I hope it helps you!

Thank you!